Complex stack or core windings are required for certain motor and sensor applications. For example, the stator and rotor windings used in angle sensitive transformer resolvers require a complex distribution of annular turns for measuring angles. Typically, a tapered distribution of copper turns on iron teeth is utilized.
For high resolution angle resolvers, the teeth of the stack are formed correspondingly closer together. At sufficiently high resolutions the high density of the teeth and narrowness of the slots prevent a wire feed winding needle from passing through the slots between teeth to form the turns of wire. Yet turns of wire must be wound at different controlled depths on the teeth and with spans extending around different numbers of teeth. Furthermore, the turns may have to be formed within the small space defined by an annular stack with inwardly projecting teeth.
Conventional flying head core winding machines do not lend themselves to achieving such distributions. In particular, they are inapplicable to annular stack configurations having teeth extending radially inwardly. The typical single and double flier type core winding machines such as, for example, described in U.S. Pat. Nos. 3,973,738; 3,857,172; 3,705,459; and 2,949,554 are adapted for winding around radially outwardly projecting teeth only. Even with radially outwardly projecting teeth flying head machines generally wind only large spans of teeth and cannot wind turns of wire around single teeth or small spans.